THE PULMONARY FUNGUS, HAPLOSPORANGIUM PARVUM, AND ITS RELATIONSHIP WITH SOME HUMAN PATHOGENS

Abstract

In a survey of the wild rodents of Alberta it was found that 14 animals contained, within their lungs, fungous cells visible to the naked eye. From the lungs of 8 of these infected animals, Haplo-sporangium parvum was isolated. The position of the fungus among the Phycomycetes is confirmed by a study of the reproductive structures, which may be interpreted as sporangia containing one or, rarely, several spores. H. parvum grows and sporulates on soil. The sporangia are adhesive and transferred by contact. At 37 [degree]C they enlarge as much as 10 times their original diam. to form thick-walled chlamydo-spores that germinate at room temp. The parasite within the lung has a diam. as much as 50 times that of the sporangium from which it must have originated. Infected lungs usually show little reaction. Only one lung was frankly gran-ulomatous. Some human systemic Phycomycetes, like H. parvum, are filamentous in their saprophytic phase and unicellular in their parasitic phase; 3 of them, Blastomyces der-matiditis, B. brasiliensis, and Histoplasma capsulatum, are closely related to H. parvum. In their saprophytic phase they all reproduce by adhesive conidia that may be interpreted as sporangia with single endospores, while in their parasitic phase no sporangia were observed. Coccidioides immitis is less closely related to H. parvum. When growing saprophytically it reproduces by air-borne oidia; when growing parasitically, by endospores.